The present invention generally relates to a combustion enhancing system employed with a stoker for burning fuel. More specifically, the combustion enhancing system includes an air foil fixed to the moving grate of the stoker. The air foil provides non-aqueous combustion enhancing fluids to the bed of fuel traveling along the grate, thereby enhancing burning of the fuel and increasing the efficiency of the stoker.
Stokers are employed for the mass burning of fuels. They generally function to feed fuel to a furnace combustion area, to distribute a supply of air to the fuel, and to retain the fuel until complete combustion is accomplished. Typically, the fuel is fed through the combustion area of the stoker by a moving or vibrating grate. The grates of conventional vibrating grate stokers are formed of a series of tuyers or keys, usually made of metal alloy or cast iron, which allow passage of combustion air through the underside of the grate to the fuel located on the top of the grate.
Efficiency of the stoker is measured by the completeness of the combustion of the fuel and the amount of pollutants resulting from that combustion. The type of fuel being burned also determines the stoker""s efficiency. For example, coal is the typical fuel employed with a stoker and the more carbon in the coal that is burned the more efficient the stoker. Other fuels burned in conventional stokers are wood, and refuse materials or waste products.
However, conventional stokers fail to burn fuel, such as coal, efficiently, because the fuel travels through oxygen deficient zones in the combustion area of the stoker, resulting in incomplete fuel combustion. Also, the conventional stokers are inefficient because they do not account for impurities in the fuel, agglomerated fuel, or for encapsulation or swelling of the fuel where the fuel becomes resistant to the combustion air. An additional problem with conventional stokers is that they do not minimize pollutants resulting from the burning of the fuel.
Commonly owned U.S. Pat. No. 5,588,378 to Mancini entitled Combustion Enhancement System With In Bed Foils, addresses the above problems by employing a plurality of combustion enhancing air foils with a stoker having a conventional traveling belt type grate. The subject matter of U.S. Pat. No. 5,588,378 is herewith incorporated by reference. However, no prior art addresses the above problems with respect to stokers utilizing conventional moving grates other than traveling grates, such as vibrating or pusher type grates.
Examples of other prior art stokers are disclosed in the following U.S. Pat. Nos.: U.S. Pat. No. 697,620 to Green et al.; U.S. Pat. No. 3,152,562 to Cohen et al.; U. S. Pat. No. 4,510,873 to Shigaki; and U.S. Pat. No. 4,876,972 to Mrklas.
Accordingly, a general object of the present invention is to provide a combustion enhancing system that improves the fuel burning efficiency of a stoker.
Another general object of the present invention is to provide a combustion enhancing system that reduces the pollutants produced by the stoker.
A further object of the present invention is to provide a combustion enhancing system that includes an air foil for distributing a non-aqueous combustion fluid in an oxygen deficient zone of the stoker, thereby optimizing combustion of the fuel.
A yet further object of the present invention is to provide a combustion enhancing system that includes an air foil for distributing emission reducing agents, thereby reducing the pollutants produced by the stoker.
Another object of the present invention is to provide a combustion enhancing system that includes an air foil fixed to the grate of the stoker, with the grate being a vibrating stoker.
Still another object of the present invention is to provide a combustion enhancing system that includes an air foil fixed to the grate of the stoker, to facilitate breaking up of the fuel and thereby making the fuel less resistant to the combustion air of the stoker and exposing more surface area of the fuel for improved combustion.
Yet another object of the present invention is to provide a combustion enhancing system that includes an air foil that can be retro-fitted to existing stokers and is relatively easy to manufacture and install.
The foregoing objects can be basically attained by a combustion enhancing member for use in a stoker combustion system having a grate for supporting a bed of fuel, the combustion enhancing member comprising an inner wall portion defining a first chamber and a second chamber, the first chamber having a first fluid inlet for receiving a first fluid and at least one fluid outlet for ejecting the first fluid, and the second chamber having a second fluid inlet for receiving a second fluid; and an upper fuel engaging surface for engaging the bed of fuel, the fluid outlet being disposed in the upper fuel engaging surface allowing ejection of the first fluid in the direction of the bed of fuel.
The foregoing objects are also obtained by a stoker combustion system, comprising a grate having a support surface for supporting a bed of fuel; a first fluid supply system for supplying a combustion fluid to the support surface of the grate; a combustion enhancing member disposed on the support surface of the grate, the combustion enhancing member including a wall portion defining a first chamber, the first chamber having a first fluid inlet for receiving a first fluid and at least one fluid outlet for ejecting the first fluid, and a fuel engaging surface for engaging the bed of fuel, the fluid outlet being disposed in the fuel engaging surface allowing ejection of the first fluid in the direction of the bed of fuel; and a second fluid supply system for supplying the first fluid to the first fluid inlet of the combustion enhancing member.
The foregoing objects can also be obtained by a method of fitting a combustion enhancing member with a pre-existing stoker combustion system, the pre-existing stoker combustion system having a moving grate with a support surface for supporting a bed of fuel, and a first fluid supply system for providing combustion fluid to the bed of fuel, comprising the steps of providing a combustion enhancing member having a chamber with a fluid inlet for receiving a first fluid, and a fluid outlet for ejecting the first fluid, and a fuel engaging surface for supporting the bed of fuel; engaging the combustion enhancing member with the support surface of the grate; and supplying a pressurized fluid from a second fluid supply system to the bed of fuel through the fluid outlet of the combustion enhancing member.
Other objects, advantages and salient features of the invention will become apparent from the following detailed description which taken in conjunction with annexed drawings, discloses the preferred embodiments of the present invention.